IDEA: How to suppress warnings for spelling typos?

You can disable that in the Inspections menu. Click on the little green box at the top of source code, or navigate to File > Settings > Inspections, under the Project Settings divider. You can then untick the box shown below.

You can use following @SuppressWarnings

For example idea is complaining about "contentid" that should be "contentId" according to him

@SuppressWarnings("SpellCheckingInspection")
public static final String ARG_CONTENT_ID = "contentid";

SUPPRESSION facility for ANY inpection is built in :

Pay attention to right arrows on the menus.